The present invention relates to a device for actuating a seat element, of the type comprising:
an actuator fitted with a transducer adapted so as to deliver a state information representative of the current position of the actuator,
a unit for controlling said actuator, linked to the said transducer so as to receive the said state information representative of the position of the actuator, the control unit comprising:
means for registering a reference state information representative of the position of the actuator for an identified reference position of the element,
means for storing said reference state information; and
means for driving the actuator so as to move the seat element towards at least one predetermined target position of the seat element other than the reference position.
In order to improve the comfort of the user, numerous seats are nowadays fitted with electric actuation devices making it possible to alter the configuration of the seat by moving movable elements thereof. In particular, such seats are in particular used in transport vehicles such as aircraft, boats and railway cars.
It is common for each seat to comprise a tiltable back articulated to one end of a seat bottom, as well as a legrest, articulated to the other end of the seat bottom. The back and the legrest can both be moved between a substantially vertical position and a substantially horizontal position, thus allowing the seat to take several configurations. For example, among these configurations are provided a user reclining configuration in which the back and the legrest are both substantially horizontal and a sitting configuration in which the legrest and the back are both substantially vertical.
An actuation device is provided for each element of the movable seat.
Moreover, numerous seats are equipped with devices making it possible through a single command to move both the legrest and the footrest and to do so, in order to bring the seat, through a single command, into a predetermined configuration.
For each of these predetermined configurations of the seat, a predetermined position is fixed for each seat element.
In order at each instant to ascertain the position of the various seat elements, and thus be able easily to manage their movement, it is known practice to provide in the devices for actuating the seat elements a transducer such as a potentiometer making it possible to gather state information representative of the position of each actuator.
In order to ensure satisfactory movement of each seat element and correct tracking of its position, it is known practice to store a reference state information representative of the position of the actuator for a reference position of a relevant seat element. All the movements of the seat element are referenced with respect to this reference position specific to the seat element.
Thus, for each of the seat""s predetermined configurations accessible through a single actuation device, the travel of the actuator required in order for the seat element to reach the desired target position from its reference position is determined.
From the desired travel of the actuator, an increment value is deduced for the state information registered by the transducer corresponding to this travel. Thus, to bring an element of the seat to a predetermined position, the actuator is activated until the current state information delivered by the transducer is equal to the reference state information incremented by an increment value corresponding to the anticipated travel of the actuator.
This solution operates in a satisfactory manner. However, when several seats are disposed side by side, as for example in a row of aircraft seats, it is found that, when all the seats are brought into one and the same predetermined configuration, the positions of each of the seat elements are not strictly identical.
Specifically, owing to the manufacturing tolerances of the mechanical structure of the seats and to the inaccuracies in the transducers used, even though, initially, the relevant seat elements are correctly aligned, after moving them along a travel corresponding to one and the same increment value in respect of the state information emanating from the transducer, the actual positions of the seat elements are not strictly identical, this being manifested as slightly different configurations of the seats, even though the commands given to each of the seats are identical.
Thus, the visual appearance of the assembly of seats is spoilt. Moreover, since the users who control their seat in a similar manner do not obtain strictly the same position for each of the elements of the seats, some of them may experience frustration.
The aim of the invention is to propose a device for actuating a seat element, making it possible to ensure that the position reached by the seat element is actually the anticipated position, and in particular that, when several seats equipped with this device are installed side by side, they react in a similar manner when they are operated so as to reach an identical predetermined configuration.
To this end, the subject of the invention is a device for actuating a seat element of the aforesaid type, characterized in that the said control unit comprises:
means for registering at least one additional reference state information, each representative of the position of the actuator for a predetermined target position of the seat element;
means for storing the or each additional reference state information; and said control unit is adapted so as, when a movement of the seat element towards a predetermined target position or towards the reference position is commanded, to activate the actuator until the current reference state information delivered by said transducer is equal to said reference state information stored for said seat element position designated by the command.
According to particular embodiments, the device comprises one or more of the following characteristics:
said transducer is a potentiometer; and
said reference state information and said additional reference state information are three in number.
The invention also concerns a seat comprising at least one movable element and at least one actuation device such as defined hereinabove mechanically associated with a seat element for its movement.
According to particular embodiments, the seat comprises one or more of the following characteristics:
it comprises at least two movable elements, each mechanically associated with an actuation device as defined hereinabove, and it comprises a device adapted so as, under the action of a single command delivered by the user, to bring the seat into at least one predetermined configuration, and said predetermined target positions or said reference position of the seat elements are the positions of the seat elements in the or each predetermined configuration of the seat; and
the said predetermined configurations of the seat comprise a mealtime configuration, a landing configuration, and a reclining configuration.
Finally, the invention concerns an assembly of seats, comprising at least two seats of similar structure, as are defined hereinabove.
According to a particular embodiment, the predetermined target positions and the reference positions of the corresponding seat elements are identical.